Development of residual stress and uniaxial magnetic anisotropy during growth of polycrystalline Co film

Abstract Growth of e-beam evaporated Co films on Si (001)/SiO2 substrate has been studied using real-time multi-beam optical stress sensor (MOSS), four probe resistivity (FPR) and in-situ magneto-optic Kerr effect (MOKE) measurements. While MOSS and FPR provide information about internal stress and film morphology, MOKE provides information about magnetic properties, thus making it possible to correlate the evolution of film stress and morphology with that of uniaxial magnetic anisotropy (UMA) in the film. Film grows via Volmer–Weber mechanism, where islands grow larger to impinge with other islands and eventually coalesce into a continuous film at around 10 nm thickness. Development of tensile stress in the film is found to be associated with the island coalescence process. The film exhibits a well-defined UMA, which varies synchronously with internal tensile stress developed during growth, suggesting that the observed UMA originates from minimization of magnetoelastic and morphological anisotropic energies in the presence of internal stress. Absence of UMA in Co film having Ag underlayer in the form of islands is understood in terms of random short-range stress in the film caused by arbitrary pinning by the Ag islands.